Thylacine (Tasmanian Tiger) Sighting Reports: United Kingdom (U.K.)
Reports from other countries can be accessed here.
The Girt Dog of Ennerdale. A livestock-killing predator that terrorised Cumberland in 1810[-1811?]. The beast was said to have been striped, and to have attacked many sheep, leading to modern speculation that it was an escaped thylacine (Freeman, 1999). However, both scientific and social evidence suggests that the thylacine was not a serious livestock pest, and that other factors were to blame for most Tasmanian farmers' losses.
Moreover, 1810 would be extraordinarily early for a thylacine to have made its way to the UK. With little chance of smuggling it such a long distance on a ship unnoticed, the absence of contemporary reports of such an attempt is good evidence that such a journey never took place. In reality, the animal could have been anything. If we accept that the animal had stripes, then a more natural candidate, as has been pointed out, would be a hyena.
The first paragraph from Richard Feeman's article 'The case of the British thylacine':
"In the spring of 1810, a bizarre series of livestock killings began. Over the next six months, a mystery predator cut a bloody swathe through Cumberland. This creature was never identified, but became known as the Girt Dog of Ennerdale. Though often quoted, this chapter In British animal mysteries is one of the most cryptic and obscure. On re-reading the tales recently, I found a strange thread that no-one (to my knowledge) has picked up on before. The saga of the Girt Dog may be even odder than anyone has ever realised: and the 'Dog' itself may be a doubly Fortean beast."
Source: Freeman, Richard. (1999). The case of the British thylacine. Animals & Men 19: 16-18.
"In 1810 a savage predator began mercilessly killing sheep in the Cumberland valley of Ennerdale. The attacks went on for months with up to eight sheep a day being slaughtered. Alarm spread, children were kept inside for safety’s sake and a £10 reward was offered for its capture.
Eventually it was spotted but it was not what the locals expected. It was described as having the qualities of both a large cat and a large dog, tawny in colour with dark stripes running down its back."
Source: Rothery, Emily. (2015). The tale of the mysterious Girt Dog of Ennerdale. Lancashire Life, 3 April.
"On April 7, at 3:30 A.M., Joan Gilbert spotted a "strange striped creature half cat and half dog" as it passed in front of her car's headlights. "It was," she recalled, "the most peculiar animal I have ever seen. It had stripes, a long thin tail, and seemed to be all gray, though it might have had some yellow on it. Its ears were set back like a member of the cat family, and it was as big as a medium-sized dog. It was thin, and it definitely was not a fox." It was, she learned when she looked through reference books at the library, an animal she had never heard of: a thylacine...on the outskirts of Bournemouth. In England."
Source: Clark, Jerome. (2013). Thylacines, pp. 198-208. Unexplained!: Strange Sightings, Incredible Occurrences, and Puzzling Physical Phenomena, third edition. Canton, Michigan: Visible Ink Press.
"I remembered reading a a couple of years back about a Thylacine sighting in the UK during the 70s."